UPDATE 4-Attacks on Kenyan churches kill 17

* Kenya hit by series of blasts since troops sent to Somalia
(Adds White House statement)

By James Macharia

NAIROBI, July 1 (Reuters) - Masked assailants launched
simultaneous gun and grenade raids on two churches in a Kenyan
town on Sunday, killing at least 17 people in the worst attack
in the country since Kenya sent troops into Somalia to crush al
Shabaab militants.

More than 60 people were wounded in the attacks in Garissa,
the north Kenya town which has been used as a base for
operations against al Qaeda-linked insurgents in Somalia.

"This is the worst single attack since October, when our
troops went into Somalia," national police spokesman Eric
Kiraithe told Reuters.

"It is the worst in terms of the numbers killed, the manner
of execution, the anger behind it and the anguish it has aroused
as well as the national impact it has had."

There was no immediate claim of responsibility for the
attacks in Garissa, a largely Muslim town of 150,000 with a
significant ethnic Somali population.

Police said they suspected al Shabaab sympathisers or
bandits may have been behind the raids, but it was too early to
say. In Somalia, al Shabaab declined to comment.

White House spokesman Jay Carney said the United States
"strongly condemned" the attacks at a time of transition in the
country. Kenya is due to hold an election next March.

Regional deputy police chief Philip Ndolo told Reuters from
Garissa that seven attackers had hurled grenades into the
Catholic Church and the African Inland Church (AIC) and then
opened fire with assault rifles.

They struck the churches, situated 3 km (two miles) apart,
at around 10.15 a.m. (0715 GMT). Two policemen guarding the AIC
church following previous attacks were among those killed.

"The goons were clad in balaclavas," said Ndolo.

"You can imagine for such a small town how the police and
medical services have been stretched trying to deal with this."

Television footage showed benches knocked over at the AIC
church and blood pooled on the floor and spattered over the
walls. Garments, shoes and bibles were strewn around.

Police milled outside the churches which were cordoned off
by investigators who were picking at fragments and taking notes.

Paul Mwalali, 52, a worshipper at the AIC church, told the
Daily Nation newspaper he heard objects hit the roof before
explosions rocked the church.

"I had a front row seat in the church. I heard something
fall on the roof. Then there was a huge explosion. I (fell) on
the ground. Then there was shooting and people were screaming,"
he said.

Felix Kimanzi told the newspaper he saw masked gunmen hurl
two grenades, but only one exploded.

"I was 100 metres away from the church when I saw two gunmen
at the entrance spray bullets at the congregation," he said.

"They were joined by two more gunmen in blue uniforms who
hurled grenades and they all fled on foot."

"COWARDLY ACTS"

Seven people who were badly wounded in the attacks were
airlifted to Nairobi from Garissa.

The attacks were the latest on Christian worshippers in
Kenya after two people were killed in grenade blasts in March
and April in Nairobi and Mombasa.

The latest coordinated assault resembled the tactics of
Nigeria's Islamist militant group Boko Haram, which has killed
hundreds of people on the other side of the continent since the
movement started its uprising more than two years ago.

Vice President Kalonzo Musyoka condemned the Garissa attacks
and said Kenya would not be intimidated by such "cowardly acts"
aimed at instilling fear.

The Supreme Council of Kenya Muslims condemned the assault,
saying "all places of worship must be respected."

Garissa, a market centre for the trade in camels, donkeys,
goats and cattle, is about 100 km (60 miles) from Kenya's Dadaab
refugee camp, where gunmen kidnapped four aid workers and killed
a driver on Friday before fleeing towards the border with
Somalia.

Kenyan forces thrust into Somalia after raids in the border
region and kidnappings that threatened the tourism industry in
the region's biggest economy and wider regional destabilisation.

Last Sunday, three people were killed in a grenade attack at
a night club in the port city of Mombasa, a day after the U.S.
embassy in Kenya warned of an imminent attack on the city.